diff --git a/core/state/state_object.go b/core/state/state_object.go
index 091d24184af584c7cf3f4c86b33755031b177118..0b72d01140d7bdfa52c0292bae7c7388baed2de7 100644
--- a/core/state/state_object.go
+++ b/core/state/state_object.go
@@ -79,7 +79,7 @@ type stateObject struct {
cachedStorage Storage // Storage entry cache to avoid duplicate reads
dirtyStorage Storage // Storage entries that need to be flushed to disk
-
+ originalValue Storage // Map of original storage values, at the beginning of current call context
// Cache flags.
// When an object is marked suicided it will be delete from the trie
// during the "update" phase of the state transition.
@@ -117,6 +117,7 @@ func newObject(db *StateDB, address common.Address, data Account) *stateObject {
data: data,
cachedStorage: make(Storage),
dirtyStorage: make(Storage),
+ originalValue: make(Storage),
}
}
@@ -184,11 +185,16 @@ func (self *stateObject) GetState(db Database, key common.Hash) common.Hash {
// SetState updates a value in account storage.
func (self *stateObject) SetState(db Database, key, value common.Hash) {
+ prev := self.GetState(db, key)
self.db.journal.append(storageChange{
account: &self.address,
key: key,
- prevalue: self.GetState(db, key),
+ prevalue: prev,
})
+ if _, isSet := self.originalValue[key]; !isSet {
+ // original value has not been set, so set it now
+ self.originalValue[key] = prev
+ }
self.setState(key, value)
}
@@ -210,6 +216,10 @@ func (self *stateObject) updateTrie(db Database) Trie {
v, _ := rlp.EncodeToBytes(bytes.TrimLeft(value[:], "\x00"))
self.setError(tr.TryUpdate(key[:], v))
}
+ // Clean the map containing 'original' value of storage entries
+ for k, _ := range self.originalValue {
+ delete(self.originalValue, k)
+ }
return tr
}
@@ -280,6 +290,7 @@ func (self *stateObject) deepCopy(db *StateDB) *stateObject {
stateObject.code = self.code
stateObject.dirtyStorage = self.dirtyStorage.Copy()
stateObject.cachedStorage = self.dirtyStorage.Copy()
+ stateObject.originalValue = self.originalValue.Copy()
stateObject.suicided = self.suicided
stateObject.dirtyCode = self.dirtyCode
stateObject.deleted = self.deleted
diff --git a/core/state/statedb.go b/core/state/statedb.go
index 101b03a127534db310cf039b8e554fbe1477e7ef..d9300012d63ceb5bd4f461e51140e68f673aa5e3 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -169,11 +169,22 @@ func (self *StateDB) Preimages() map[common.Hash][]byte {
return self.preimages
}
+// AddRefund adds gas to the refund counter
func (self *StateDB) AddRefund(gas uint64) {
self.journal.append(refundChange{prev: self.refund})
self.refund += gas
}
+// SubRefund removes gas from the refund counter.
+// This method will panic if the refund counter goes below zero
+func (self *StateDB) SubRefund(gas uint64) {
+ self.journal.append(refundChange{prev: self.refund})
+ if gas > self.refund {
+ panic("Refund counter below zero")
+ }
+ self.refund -= gas
+}
+
// Exist reports whether the given account address exists in the state.
// Notably this also returns true for suicided accounts.
func (self *StateDB) Exist(addr common.Address) bool {
diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
index f9eea319e1213cf4029d868af38605da0dc4accd..aee6d6f6d735ab2be5bb6f5a63d800f270dd7c54 100644
--- a/core/vm/gas_table.go
+++ b/core/vm/gas_table.go
@@ -17,9 +17,11 @@
package vm
import (
+ "bytes"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/params"
+ "math/big"
)
// memoryGasCosts calculates the quadratic gas for memory expansion. It does so
@@ -115,7 +117,7 @@ func gasReturnDataCopy(gt params.GasTable, evm *EVM, contract *Contract, stack *
return gas, nil
}
-func gasSStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+func gasSStoreOld(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
var (
y, x = stack.Back(1), stack.Back(0)
val = evm.StateDB.GetState(contract.Address(), common.BigToHash(x))
@@ -137,6 +139,61 @@ func gasSStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, m
}
}
+func gasSStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
+ var (
+ y, x = stack.Back(1), stack.Back(0)
+ current = evm.StateDB.GetState(contract.Address(), common.BigToHash(x))
+ )
+ //1. If current value equals new value (this is a no-op), 200 gas is deducted.
+ //2. If current value does not equal new value
+ // 2.1 If original value equals current value (this storage slot has not been changed by the current execution context)
+ // 2.1.1 If original value is 0, 20000 gas is deducted.
+ // 2.1.2 Otherwise, 5000 gas is deducted. If new value is 0, add 15000 gas to refund counter.
+ // 2.2 If original value does not equal current value (this storage slot is dirty), 200 gas is deducted. Apply both of the following clauses.
+ // 2.2.1 If original value is not 0
+ // 2.2.1.1 If current value is 0 (also means that new value is not 0), remove 15000 gas from refund counter. We can prove that refund counter will never go below 0.
+ // 2.2.1.2 If new value is 0 (also means that current value is not 0), add 15000 gas to refund counter.
+ // 2.2.2 If original value equals new value (this storage slot is reset)
+ // 2.2.2.1 If original value is 0, add 19800 gas to refund counter.
+ // 2.2.2.2 Otherwise, add 4800 gas to refund counter.
+ new := common.BigToHash(y)
+ if current == new {
+ // 1. current == new
+ return 200, nil
+ }
+ // Todo, get this value
+ original := common.Hash{}
+
+ // 2
+ if original == current { // 2.1
+ if original == (common.Hash{}){ // 2.1.1
+ return 20000, nil
+ }
+ // 2.1.2
+ if new == (common.Hash{}){
+ evm.StateDB.AddRefund(15000)
+ }
+ return 5000, nil
+ }
+ // 2.2
+ if original != (common.Hash{}){ // 2.2.1
+ if current == (common.Hash{}){ // 2.2.1.1
+ evm.StateDB.SubRefund(15000)
+ }else{
+ // 2.2.1.2
+ evm.StateDB.AddRefund(15000)
+ }
+ }
+ if original == new { // 2.2.2
+ if original == (common.Hash{}){
+ evm.StateDB.AddRefund(19800)
+ }else{
+ evm.StateDB.AddRefund(4800)
+ }
+ }
+ return 200, nil
+}
+
func makeGasLog(n uint64) gasFunc {
return func(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
requestedSize, overflow := bigUint64(stack.Back(1))
diff --git a/core/vm/interface.go b/core/vm/interface.go
index d176f5b3977b21cdaa9b638f48fe444aefdcdb61..a5a3ff3e32cf6e65170f2892b43f0b0592c5229a 100644
--- a/core/vm/interface.go
+++ b/core/vm/interface.go
@@ -40,6 +40,7 @@ type StateDB interface {
GetCodeSize(common.Address) int
AddRefund(uint64)
+ SubRefund(uint64)
GetRefund() uint64
GetState(common.Address, common.Hash) common.Hash
diff --git a/core/vm/noop.go b/core/vm/noop.go
index b71ead0d777de36a6c37035b0fdc6762d5e0ed63..c7ed2e4515c5de895903b767a4515b741b8cebd2 100644
--- a/core/vm/noop.go
+++ b/core/vm/noop.go
@@ -56,6 +56,7 @@ func (NoopStateDB) GetCode(common.Address) []byte
func (NoopStateDB) SetCode(common.Address, []byte) {}
func (NoopStateDB) GetCodeSize(common.Address) int { return 0 }
func (NoopStateDB) AddRefund(uint64) {}
+func (NoopStateDB) SubRefund(uint64) {}
func (NoopStateDB) GetRefund() uint64 { return 0 }
func (NoopStateDB) GetState(common.Address, common.Hash) common.Hash { return common.Hash{} }
func (NoopStateDB) SetState(common.Address, common.Hash, common.Hash) {}